สถาบันวิจัยวิทยาศาสตร์สาธารณสุข

NATIONAL INSTITUTE OF HEALTH OF THAILAND

Field Efficacy of Herbal Repellent against Biting Midges in Thailand

Authors : A. Tawatsin1, U. Thavara1, J. Chompoosri1, P. Bhakdeenuan1, P. Kunhachan1, S. Sangkitporn1, P. Siriyasatien2,3
Affiliations : 

1 National Institute of Health, Department of Medical Sciences, Ministry of Public Health, Nonthaburi, Thailand,
2Chulalongkorn University, Faculty of Medicine, Department of Parasitology, Bangkok, Thailand,
3Excellence Center for Emerging Infectious Diseases, King Chulalongkorn Memorial Hospital, Thai Red Cross Society, Bangkok, Thailand          

 

Source : The 14th Conference of the International Society of Travel Medicine 24-28 May 2015, Quebec City ,Canada

 
Language : English 
 

Abstract :

 
 

        Biting midges are nuisance pests usually found on the shorelines and sandy beaches. They feed on tourists and resident visiting the beaches and resorts. These insects deter human recreation and also diminish tourism industry. In Thailand, Leptoconops spinosifrons is one of the predominant species of biting midges and has been found on various beaches in 9 provinces (Trat, Chantaburi, Rayong, Chonburi, Prachuab Kirikhan, Chumporn, Surat Thani, Nakhon Si Thammarat, Songkhla) around the Gulf of Thailand and 6 provinces (Ranong, Phang Nga, Krabi, Trang, Satun, Phuket) along the Andaman Sea, including some islands located in both seas. Since the control of biting midges along beaches by larvicides or adulticides is hardly possible, attempts have been made then to prevent its nuisance by using repellent application. An herbal repellent, containing essential oils from Eucalyptus citriodora Hook. and  Litsea cubeba (Lour.) Pers., was evaluated for repellency against  L. spinosifrons in comparison withN,N-diethyl-3-methylbenzamide (deet). Both repellents were prepared as 20% in ethanol and each one was applied on the clothes (long sleeve T-shirt and pants) at the dosage of 0.5 mg a.i./cm2. Assessments were made using landing rates on the treated clothes as compared with controls (untreated clothes). Both repellents showed relatively high repellency against L. spinosifrons; however, the herbal repellent provided higher degree of repellency (98.3 - 99.7%) than did deet (82.7 - 98.5%). This study demonstrates a high potential for use of the herbal repellent to protect from biting of  L. spinosifrons.